Gene amplification (amp) is one of the basic
mechanisms connected with overexpression of oncogenes.
The c-MYC (located in 8q24) and MLL (located
in 11q23) are the most often over represented genes
that lead to a rapid proliferation of the affected cell
clone in patients with myeloid neoplasms. Assessment
of the level of amp c-MYC or amp MLL in the cases
with trisomy 8 (+8) or trisomy 11 (+11) and myeloid
malignances is necessary for a more precise estimation
of the disease progression.
A total of 26 patients with acute myeloid leukemia
(AML) and myelodysplastic syndromes (MDS) were
included in the study: 18 with +8, six with +11 and
two with complex karyotypes suspected of the partial
trisomy. Routine cytogenetic analysis and fluorescent
in situ hybridization (FISH) were applied to indicate
the chromosome alterations and genes amp in the bone
marrow cells.
Amp c-MYC was observed in 12 from 18 (66.7%)
patients with +8. All the patients with +11 demonstrated
a different level of amp MLL. In most of the cases
with MDS (9/10), the coincidence of the +8 or +11
with amp c-MYC or amp MLL, respectively, leads to
transformation to AML and/or short overall survival.
Our data suggest that amp c-MYC and amp MLL develop
in conformity with +8 and +11, especially in
cases with progressive deviations in the karyotype as
an aggressive expansion of an aberrant cell clone and
appearance of additional chromosome anomalies.